function A0_coef = RK3_burger(A0_coef,dt,k,N,M,b_fun,db_fun)
New_A0 = one_step_burger(A0_coef,k,N,M,b_fun,db_fun);
A1_coef = A0_coef + dt*New_A0;
A1_coef = 0.75*A0_coef + 0.25*A1_coef + 0.25*dt*one_step_burger(A1_coef,k,N,M,b_fun,db_fun);
A0_coef = (1/3)*A0_coef + (2/3)*A1_coef + (2/3)*dt*one_step_burger(A1_coef,k,N,M,b_fun,db_fun);
end